Styrene, also known as vinyl benzene, is an aromatic compound that is produced in industrial quantities from ethyl benzene. The most common method of styrene production comprises the dehydrogenation of ethylbenzene, which produces a crude product of styrene and ethylbenzene. Polystyrene is an aromatic polymer produced from the styrene monomer. Polystyrene is a widely used polymer found in insulation, packaging, disposable cutlery, and foam cups.
Expanded polystyrene (EPS) is well known and can be produced by combining an expandable gas, such as CO2, with polystyrene, such as during the production of foamed products and can include extruded polystyrene (XPS). EPS can be used in applications such as insulation material as the entrapped gaseous content resists the flow of heat thereby giving insulating properties. EPS can be used in applications in packaging providing protection from impact due to the entrapped gaseous content. Other types of polystyrene include elastomer-reinforced polymers of monovinylidene aromatic compounds such as styrene, a-methylstyrene, and ring-substituted styrene that can be useful for a range of applications including food packaging, office supplies, point-of-purchase signs and displays, housewares and consumer goods, building insulation, and cosmetics packaging. Such elastomer-reinforced polymers are commonly referred to as impact modified or high impact polystyrene (HIPS) while a styrene homopolymer may be referred to as general-purpose polystyrene (GPPS).
Byproducts and excess amounts of polystyrene and polystyrene containing compositions are produced during the process of molding, shaping and producing the products containing polystyrene. These byproducts, along with post commercial, post consumer polystyrene products, often become waste that can end up in landfills or incinerators. It is desirable to recycle this material in order to prevent waste and pollution. It is also desirable to obtain polystyrene having improved tensile properties in order that a lesser amount of polystyrene may be needed in a given polystyrene product, which can result in an overall reduction in polystyrene waste.